Telephone system



Allg. 5, 1935. R. HoEFl-:RT ET AL 2,010,365

TELEPHONE SYSTEM Filed Oct. 14, 1932 3 Sheets-Sheet l www Aug. 6, 1935. R. Hor-:PERT Er AL TELEPHONE SYSTEM 3 Sheets-Sheet 2 Filed 001'.. 14, 1952 ug. 6, v1935.` R, HOEFERT ET AL 2,010,365

TELEPHONE SYSTEM cording to the invention, the connecting traino Patented y Aug.v 6, 1935 UNITED STATES TELEPHONE SYSTEM Reinhold Hoefert and Eduard Wehinger, Berlin,

Germany, assignors to Siemens Lf Halske Aktiengesellschaft, Germany Application October 14,

Siemensstadt, near Berlin,

193.2, serial N0. 637,748k

In France October 19, 1931 Claims.

The invention relates to a circuit arrangement for telephone systems .and has -for its object to facilitate connecting traffic-'between semi-auto- `matic and completely automatic exchanges. Ac-

is carried out in the following manner:

In semi-automatic traffic a calling subscriber has access over automatically set numerical impulse receivers to an exchange operator who, according to requirement, completesy the connection in the required traiflc direction over the connecting route over which she was Vcalled either to a subscriber of a completely Vautomatic exchange or another subscriber of a semi-automatic exchange. The connectingroute over which the 4exchange operatorpasses the call can be used in completely automatic trailic also and in such a case the setting of the numerical impulse receiver in this connecting route is controlled from thecompletely automatic exchange.

An embodimentof the Ainvention is shown in Figs. 1-3 of the drawings wherein Fig. lshows a general plan diagrammatically whereas the individual circuits associated with the repeater Ue are illustrated in Fig. `2 and those associated with the group selector IGW in Fig. 3. Y

' The features ofthe invention will rst be described in conjunction with Fig. 1 of the drawings.

When, for example, a. subscriber T5 of the local battery exchange OBI lifts his receiver, a call nder AS commences to operate in known manner to which, after completed operation, an assessor Ab is set. Over this assessor access is made to the repeater Ue which causes a secondary line switch MW to beset to an idle group selector IGW in the automatic exchange SAI. The group selector. IGW-'is automatically raised tothe rst level in which it hunts freely for an idle operators position VPL.V The rexchange operator at this position is notified of the call byl the signal lamp lighting up, whereupon she connects herself to the calling subscriber and inquires for the number required. `She is also in a position to recall said subscriber in known lmanner Ain case he, in themeantime, has replaced his receiver. r

If the calling subscriber then requires a connection with, forY example, a subscriber of the automatic exchange SA! the operator after having inserted the connecting plug in the appropriate jack causes theV group'selector and the `numerical impulse receiver succeeding said group selector to be set in .a manner of no interest in vthe present case.l

Should the subscriber, however, require a connectionl with, for example, the subscriber T4 of the automatic exchange SA2, she transmits impulses over the line over which she was called.

the identification digit for the junction line seize for the call is then suppressed due to the fact that the operator is already connected to this line. The second impulse series, however, inuences the group selector GW in the automatic exchange SAQ accessible over the repeater Ue. This group selector is set in known manner to an idle nal selector, for example, LW, which in turn is ultimately set to the required subscribers line by means of additional impulse series transmitted by the operator.

In the case of the calling subscriber requiring a connection with the subscriber of his own local Vbattery exchange, for example, the subscriber T6, the impulse series denoting this line causes the group selector GW in the local battery exchange 'OBS to be influenced, which in turn obtains ac- Ycess to a nal selector LW capable of being set rto the required T-subscribers line by the succeeding impulse series transmitted by the operator.- f

The calling subscriber T5, however, has also access to subscribers of other local battery exchanges '(for example, OB2)l and is .able to set .the group selector GW in the local battery exchange OBI to a junction line leading to the local battery exchange OB2 by transmitting a corresponding impulse series. A plurality of local battery exchanges also are accessible in succession over the individual numerical impulse receivers in a similar manner.

'If a subscriber of the auto-matic exchange SA2, for example, T3, now calls instead of a subscriber of a local battery exchange, he has access over the free hunting selecting switches (call finder AS and change-over switch' UW) to an idle junction line leading to the automatic exchange SAE which may, for example, be represented by the line shown in Fig. 1 leading to the group selector IGW, that is to say the line accessible when a local battery exchange subscriber calls. This group selector is not set automatically as in the case .ci local battery subscriber calling but has to be raised to the required level by means of impulses transmitted by the calling subscriber. If, for example, a subscriber of the automatic exchange SA! (T2) is Wanted, the group selector IGW is raised to the second level, whereupon, by means of addition-al impulse series, the group selectors IIGW and IIIGW and nally the iinal Thefiirst impulse series which corresponds to f selector LW may be set to the required subscriber T2.

Should, however, the subscriber T3 not want a subscriber of this automatic exchange but, for example, a subscriber o1 his own automatic exchange (SAE), he transmits another impulse series which, by means oi the discriminator ML (also actuated by the numerical impulses) causes the switch UW to operate so that it sets its wiper to a line leading to the group selector GW in the automatic exchange SAE. The calling subscriber T3, by transmitting further impulse series, is then in a position to cause the group selector to be raised to the second level in which it hunts for an idle fina-l selector LW in the automatic exchange SAE which then in turn may be set to the required Til-subscribers line by means of additional impulse series.

I'he subscriber T3 is able to obtain a direct connection with a subscriber of a local battery exchange, for example, OBE. After having caused the switch UW to operate, he sets the group selector GW by means of a corresponding impulse series to a line leading to the repeater Ue, whereupon the line, otherwise used for calling an operator, can be utilized for calls in opposite direction. Similarly to the manner in which an operator assists in setting up a connection and described above, the numerical impulse receivers in the rural exchange OBi or in further succeeding rural exchanges, such as OBR, can then be influenced by additional impulse series.

From this general description it will be seen that a calling subscri er of a local battery exchange has access to an operators position over a group selector automatically set to an idle operator and located in an automatic exchange. This connecting route used for calling can, however, as indicated above also be utilized for automatic connections from subscribers of automatic exchanges in which case the group selector IGW is not set automatically but hunts for the required level Under the influence of numerical impulses transmitted by the calling subscriber.

The connecting route used for calling can be likewise utilized in this manner for denite connections in the opposite traino direction.

Having new described the Various switch trains in general, the switching operations performed in the individual circuits-that is to say. those of the repeater Ue and the group selector IGW- will now be described in conjunction with Figs. 2 and 3 of the drawings.

Assuming that when a subscriber of the local battery exchange calls in the ordinary manner, the assessor Ab shown diagrammatically in Fig. l has been set to the calling rural exchange, relay Ai shown in Fig. 2 is energized in a manner of no interest in this case over the a-lead, contact "msn, winding III and earth. This relay is rst placed in a locking circuit extending over cont-acts leal, 'itc and winding II. If the con1 necting route is prepared for use-that is to say, on the condition that all the devices are at normal--a locking circuit for relay Ai over winding I and also an energizing circuit for relay C are simultaneously closed over contact leal and the wiper el of the time switch Z. Winding II of relay All is then disconnected at contact '530. The closing of cont-act 69o causes relay Sp to operate over earth, relay Sp, contact 69e, resistance Wz'2, battery, earth. Winding III of relay AI also is then disconnected at contact Insp. The closing of contact 46c energizes relay An over: earth, contacts lial, flic, Mq, relay An, battery, earth. Relay R operates in the following circuit on the closing of Contact Ecm: earth, contacts dtp, 5mm, tild, relay R, battery, earth. Due to the closing or" contact 52?' the rotary mag net D of the secondary lineswitch MW receives an impulse which causes said secondary lineswitch to advance one step. Relay R is decir-- ergized on the energization oi' the rotary magnet D due to the opening of contact 55d and disconnects the rotary magnet D by opening its contact Relay R is then connected up afresh and the secondary llneswitch MW is continuously advanced due to the interaction between the rotary magnet D and relay R until it reaches an idle connecting device shown in Fig. 3. When this occurs, the undermentioned circuit is closed, since relay Ro is energized over windings I and II ci' relay Ao (without, however, influencing this rclay) when said connecting device is in its normal position and contct 95m, consequently, is closed: earth, contact Slam, windings Il and I of relay P, wiper of the secondary lineswitch MW, contact 95m, relay C0, winding I of relay Ro,

battery, earth. Relays P, Co, and Ro operate in this circuit.

Due to the opening of contact 18p on the energization of relay P, relay R remains deenergized with the result that the secondary lineswitch MW cannot be further advanced. The speaking leads ings I and II of relay Ao, battery, earth. The

closing of contact mimo in Fig. 3 causes an impulse to be 'transmitted to thc vertical magnet I-IGW over: earth, battery, vertical magnet HGW, winding III of relay Por, rotary off -normal contact iswgw, contact Ilao, 99h, earth. The group selector IGW is then raised to the first level. Due to the slow-acting relay Q being energized some little time after the closing of contact 43p, the momentary current applied to relay Ao is cut oil at contact Zq, causing this relay to relapse. In addition, the vertical magnet and also winding III of relay Po` located in the circuit for said vertical magnet are now deenergized so that consequently impulses are transmitted to the rotary magnet DGW of the group selector over: earth, battery, rotary magnet DGW, oil-norma1 contact lliilcgw (closed after the rst vertical step), contact lllpo, relay interrupter RU, earth. The group selector IGW no-w hunts freely in the First level for an idle trunk to the operators position VPL. On finding this, relay Po is energized over windings I and II in known manner, whereupon contact i i ipo is opened so that the group selector is brought to rest. rIhe seized operators position is guarded by winding II of relay Po` being short circuited over contact itlfipo. The operators 'position seized by the group selector IC-iW is not shown in this case. A call signal can be produced at the operators position, for example over the Zi-lead and relay E shown in Fig. 2 (without, however, energizing this relay), while the subscriber con receive an exchange signal from the operators position indicating that he has been connected to such a position.

When the exchange operator now inserts the enquiry plug, relay I which is connected to the a-lead (Fig. 2) is energized due to a potential being applied. The energization of relay I causes relay Do and Dl to operate over contact 2i. The exchange operator is then switched through to the calling subscriber by the closing of contacts 32do and 29i.` If the subscriber in the meantime has replaced his receiver, the operator can recall him in known manner by a denite switching operation. If he has awaited the operators reply, however, said operator inquires for the number required and then completes the connection by transmitting impulses corresponding to the requiredA traiic direction.

If, for example, the calling subscriber wishes to set up a connection with a subscriber of the local battery exchange OBJ shown in Fig. l, the rst impulse series isy suppressed due to the fact that the exchange operator is already connected `to the junction line tobeused for the connection.

On the rst deenergization of relay I during the impulse transmission, relays V and Vl only are caused to operate over: earth, contacts 3i, lldl, relay V windings II and I of relay VI, battery, earth. Relays Do and DI remain energized over contact Ido during this first impulse series. After relay VI has been energized during therst impulse series, relay K is inliuenced over earth, battery, winding II of relay K, contact 250|, |2u, Vido, IBS, lgal, earth, and the calling subscriber, therefore, is disconnected due to the opening of contacts '|2lc'and 51k. At the end of the rst impulse series, that is to say on the prolonged energization of relay I with consequent deenergization of relays V and VI, relays Pl and L are causedto operate overthe following circuit due to relay K remaining energized over its contact v| ik: earth, battery, relay L, winding II of relayP cam contact of a stepping switch A, coning of contact 64p| causes the group selector GW in the automatic exchange SA? shown in Fig. l to be seized. yA circuit for the setting of this group selectoris prepared over contact 55M.

vWhen the operatork now transmits the second impulse series which may comprise four impulses, relay I is deenergized a number of times corresponding to the number of impulses transmitted and causes relay V and V! to remain energized during the whole impulse series. Due to relay L now being energized (earth, battery, L, 261,A 271), earth) the rotary magnet A of a stepping switch is intermittently influenced over earth, contacts 3", ll, switch magnet A, battery, earth. Consequently the wiper a of this stepping switch is advanced four steps. Over contact 561' the impulses for the setting of the group selector GW are transmitted, causing this group selector to be raised to the fourth level. f

` At the end of the impulse seriesthat is to say, when relay I. remains energized an extended period-relays V and VI as well as the switch magnet A are deenergized due to the opening of contact 3i. Relay U will now operate over earth, battery, relay U, switch wiper a, contacts lllvl, |51c, l'ldo, |88, |9al, earth. Relay U is placed in a locking circuit over its contact |3u. The opening of contact |2u deenergizes relay K after relay PI has released dueto the opening o1" the cam contact aI-I and relay L also has relapsed due to contact 21o being opened. The set group selector is released on the opening of contact `By means offurther impulseseries the connection to a subscriber of this local battery exchange or to a subscriberk of another rural axchange (for example CB2) can then be completed.

Ringing current is transmitted to the required subscriber in known manner of no interest in this case (automatically or by the assistance of an operator) after the connection has been set up. When the called subscriber answers, the exchange `operator withdraws the connecting plug and this causes relay I to release. Consequently, relay V and Vl are reenergized over contact 3i.

Due to this energization, however, lasting an extended period, relay Do is caused to relapse due to the short circuit over contact 6v which in turn causes relay DI to be deenergized in consequenceof contact Ido being opened, thus Gausing the release of relays V and VI. Prior to the release of relay Dl the switch magnet Z receives an impulse over earth, battery, switch magnet Z, contacts 11de, '|8dl, earth. This switch therefore executes a switching step and closes its cam contact denoted by Z|| It should be mentioned in this connection that all the contacts characterizing an open circuit comprise mechanically operated cam contacts and are set in the operative position indicated by the index. Contacts characterized by a closed circuit are only intermittentlyactuated on the energization of the corresponding switch magnet.

After the rst switching step, on the part of the stepping switch Z, as stated above, the cam contact zl-Il is closed. Relays C and Al relapse after the first switch step (switch Wiper Z l). Contact 64e, actuated on the rst energization of the switch magnet Z, causes relay RI to operate over earth, contact 86s, 84e, relay RI, resistance Will, battery, earth. The switch magnet Z therefore is deenergized after the first switch movement due to contact Brl being opened. Contact 84e also now being opened causes relay RI to release so that a fresh circuit is closed for the switch magnet Z as follows: earth, battery, switch magnet Z, contact 837i, cam `Contact z|-| earth. An interaction between the switch magnet Z and relay RI is therefore set up which continues until the stepping switch Z has been restored to its normal position and in this position reopened the cam contact a|-||. In the meantime relay U relapsed due tol the opening of contacts 'Fdo and relay Sp by contact k@Se being opened. The stepping switch A, all

the cam contacts al-l of which also are closed, is restored to normal on the advance operation Iof the part ofthe stepping switch Z over contact 8s. When relay I releases on the connecting plug being withdrawnrelay P relapses before the release v,of relay D! (short circuit over contacts l |52' and H651). They locking circuit for relays Co and Ro is consequently opened at contact-36p (Fig. 3). l.el'ay Co being a slow acting relay ren mains energized' a little while longer so that 'over contacts Qlco and 95m the primary wind- 'influenced over the secondary windingY and con- Vtacts Seco and 93m in the group selector IGW.

Winding II of relay Ao is inuenced over contact ll Ib 'and the close rotary olf-normal contact lwgw, causing relay Po to relapse due to the opening of contact Ilao. The group selector by the energization of its rotary magnet DGW over Contact H4100 is then advanced to its normal position. The opening of the rotary offv normal contact l ISwgw deenergizes winding yII of relay Ao and cuts olf relay B at contact |09ao.

The connecting device shown in Fig. 3 is thus also restored to normal. The connecting route utilized for calling is now completely released and the speaking connection extends over the rural exchange only. The release of the connection can be effected in any known manner.

If the calling subscriber wishes to set up a connection with, for example, the subscriber Te of the automatic exchange SAE, the operator transmits the second impulse series comprising -two impulsesthe rst impulse series being suppressed as stated above. This causes the group selector to be set in known manner. Due to the fact that relay U is not energized the group selector remains in the set position and additional impulse series influenced the final selector LW shown in Fig. l found by the group selector GW to be idle. The subscriber Te is then called in known manner. When he answers, a negative potential is applied to the b-lead in a manner of no interest in the present case and this negative potential causes relay Yi to be influenced over: earth, relay YI, contact Me, b-lead and negative potential in the succeeding switch. The closing of contact 901/1 causes relay S to operate over: earth, battery, relay S, contact ilyi, 35i/pl, earth. Relay S is placed in a locking circuitl over contact s and the group selector is maintained in the set position over contact 555s. Relay I is again deenergized when the connecting plug is withdrawn, whereupon the connecting route leading to the exchange operator over the secondary lineswitch MW is released .in the manner indicated above. The stepping switch Z, however, is not alone advanced into its original position under the inuence exerted by relay RS but a thermo relay Th also is inuenced with the result that the stepping switch Z takes a considerably longer 'time to advance (for example, six minutes). When relay I is deenergized on the withdrawal of the connecting plug, the stepping switch Z receives an additional impulse which causes said stepping switch to advance one step. In the meantime, however, the thermo relay Th has been influenced and starts opera-ting after a short delay, causing relay R1 to operate over Contact Vith and the energizing circuit for the switch magnet Z to be cut olic at contact ililrl. The thermo relay Th is released on the opening of contact S31-l and thereupon, after a short interval, opens its Contact 81th so that relay R l, consequently, relapses. The switch magnet Z then again receives an impulse over contact Stir! and takes a further step whereupon the thermo relay Th is influenced afresh over contact 83N. This interaction between the switch magnet Z, the thermo relay Th and relay Ri continues until the stepping switch (switch wiper ZIII) has reached a definite position in which relay Yi is short circuited over contact lial. The opening of contact Styl causes relay S to release, thus releasing the group selector GW and cutting oli further switch ytrains due to the opening oi contact 65s. The stepping switch Z is now restored to normal under the control of relay Ri in known manner and thereby causes the stepping switch A also to be restored to normal so that the complete system is set at normal after all the connecting devices have thus been forcibly cut 01T.

If now, for example, the subscriber T3 of the automatic exchange SAE is calling instead of a subscriber of a local battery exchange, the former will be switched through to the first group selector IGW over the call finder and the changeover switch in the manner indicated in Fig. 1. The connecting device shown in Fig. 3 is then seized in a similar manner, with the diiierence, however, that no potential is applied to the celead for the purpose of causing relay Ao 'to operate with the result that the vertical magnet of the group selector does not receive an impulse. Such a potential is not applied until the subscriber starts dialling and thereby causes the group selector IGW to be set in accordance with the impulses transmitted. The impulses transmitted for the setting of the group selector at the same 'time influence a discriminator switch ML diagramma-tically shown in Fig. l. If the impulse series transmitted corresponds to another traflic direction than that over which the seized group selector is accessible, the switch UW is so switched over in a manner of no interes-t in this case that it hunts for an idle group selector in the automatic exchange SAE. When access has been found to such a group selector, for example the group selector GW, the calling subscriber himself is in a position to influence this switch and cause it to be set either to a final selector LW or to the repeater Ue. liter the group selector has been set to a repeater in the manner indicated in Fig. 2, an earth. 'potential applied in a manner or" no interest to the c-lead cai relay C to operate winch by closing contact lc in turn causes the encrgization of relay Sp and consequently the disconnection of relay Al. The potential applied to the a-'lead over contacts Sie and -lii influences the local battery exchange (OBD relay which corresponds to relay I shown in When the calling subscriber now transmits impulses-that is to say, when he influences relay I over the aflead, the energizing circuit lor this relay is intermittently interrupted so that the relay in the local battery exchange corresponding to relay I is intermittently deenergized and this impulse receiving relay in the local ba tery exchange then causes the further switch train to be completed in known manner. After access has been found to the required subscriber ringing current is automatically transmitted to him so that the required speaking connection is completed when the called subscriber answers.

As will be seen from the description, the group selector IGW is automatically set when seized by a subscriber oi a local battery exchange but this automatic setting does not take place when a subscriber or" an automatic exchange calls. For a subscriber of such an exchange to influence the group selector a special .impulse series has to be transmitted.

liurthermore, it has been stated that the connecting route over which a local battery exchange subscriber calls an operator is automatically used by subscriber of automatic exchanges ior the setting up of connections to other automatic exchange subscribers as well as to subscribers of a local battery exchange. In the latter case a special impulse reversal takes place (relay I receives earth impulses and transmits potential impulses).

What is claimed is:

l. In a telephone system, two automatic offices and a semi-automatic office, a trunk line connecting the two automatic offices, a trunk line connecting one automatic oiiice and the semi-automatic oiice, subscribers lines terminating at the offices, means automatically operated responsive tol the initiation of a call on a line terminating at said one automatic oiiice for extending a connection to the other automatic office over the iirst trunk line, and means automatically operated responsive to the initiation oi a call on a line termihating at the semi-automatic office for extending a connection from the line through said one automatic otflce to the other automatic office over the two trunk lines in series.

2. A telephone system as claimed in claim 1 in which connections extended from lines terminating at the automatic oflice are further extended under directive control of the calling party and in which calls extended from lines terminating at the semi-automatic office are further extended by an operator at the terminating automatic oice.

3. A teiephone system as claimed in claim l in which different conditions are imposed on the trunk line connecting the two automatic oiiices dependent upon the omce at which the involved line terminates.

4i. Ina telephone system, a trunk line terminating in an automatic switch having a primary movement in one plane and a secondary movement in an intersecting plane, two means of access to said trunk, means for directively operating said switch in its primary movement over one means of access, means for automatically operating said switch in its secondary movement in respense to the completion of its primary movement, and means automatically responsive to the extension of a call to said trunk over said other means of access for automatically operating the switch in both its primary and secondary movements.

5. In a telephone system, two oices, an operators switchboard, a trunk connecting said oiices, subscribers lines terminating at said offices, means responsive to the initiation of a call on a line terminating at one office for extending a connection from the line to the switchboard via said trunk, switching apparatus at said one office revertively controlled over the trunk from the switchboard for further extending the connection from the calling line to a called line terminating at said one office, and means whereby a calling party on a line terminating at the other oflice is enabled to directly control said switching apparatus to extend a connection from that line to a called line in said one office. Y

6. In a telephone system, subscribers lines terminating at each ofce, a trunk line connecting the first and second omces, three branches for the trunk line at the second office, a second trunk line connecting the second and third oices, means for establishing a connection from a line in the rst oflice to a line in the third oflice over the rst trunk line, its first branch and the second trunk line, means for establishing a connection from aline in the first oflice to a line in the second oiiice over the rst trunk line and its second branch, and means for establishing a connection from a line in the second omce to a line in the first office over the rst trunk line and its third branch.

'7. A telephone system as claimed in claim 6 in which connections from a line in the iirst oflice to lines in the second and third offices are completed' under control of an operator at the third office and in which a connection from a line in the second office to a line in the first ofiice is completed under control oi the calling party.

8. In a telephone system, two automatic oflices and ya semi-automatic oflice, subscribers lines terminating at each office, a trunk line connecting the two automatic offices, a trunk line connecting one automatic oice and the semi-automatic oflice, an operators position at the other automatic cnice, means automatically operated t responsive to the initiation of a call on a line terminating at said one automatic oiiioe for extending a connection over the rst trunk line to said other automatic ofce, means controlled oy the calling party for ,releasing said connection and for extending a connection from the calling line to acalled line terminating at either said one automatic ofce or said semi-automatic oice, means responsive to the initiation of a call on a line terminating at the semi-automatic office for extending a connection from the line over the second and first-mentioned trunk lines in series to said operators position, and means controlled from said operators position for extending a connection from the calling line to a called line terminating at said one automatic oice and for releasing said iirst trunk line.

9. In a telephone system, three offices, subscribers lines terminating at each oiiice, a trunk connecting the first and second offices, a second trunk connecting the second and third oices, means responsive to the initiation or" a call on a line terminating at the second office for automatically extending a connection from the line to the third office over said second trunk, subscriber-controlled means for releasing said connection and for extendingl a connection from the calling line to a called line in either the iirst or second ofce, means responsive to the initiation of a call on aline terminating at the rst ofce for automatically extending a connection to the third oice over said first trunk and said second trunk, means controlled from the third ofce for extending a connection v from the calling line over the first trunk to a called line terminating at the second office and `for releasing said second trunk line, and means REINHOLD HOEFERT. EDUARD WOCHINGER. 

